Liquid metal micro switches (LIMMS) have been made that use a liquid metal, such as mercury, as the switching fluid. The liquid metal may make and break electrical contacts. To change the state of the switch, a force is applied to the switching fluid, which causes it to change form and move. The liquid metal may form oxide films that inhibit proper functioning of the switch. For example, the oxide film may increase the surface tension of the liquid metal, which may increase the energy required for the switch to change state.
In one embodiment, a method for reducing oxides on switching fluid is disclosed. The method includes depositing a switching fluid on a first substrate. A solid reducing material is deposited so that it contacts at least a portion of the switching fluid. The reducing material reacts with oxides on the switching fluid. Finally, the first substrate is mated to a second substrate, the first substrate and the second substrate defining therebetween a cavity holding the switching fluid, the cavity being sized to allow movement of the switching fluid between first and second states.
In another embodiment, the method comprises depositing a switching fluid on a first substrate. The switching fluid is mixed with a reducing material to react with oxides on the switching fluid. The first substrate is mated to a second substrate, the first substrate and the second substrate defining therebetween a cavity holding the switching fluid, the cavity being sized to allow movement of the switching fluid between first and second states.
In a third embodiment, the method comprises depositing a switching fluid in a switching fluid channel. An actuating fluid mixed with reducing material is deposited on a first substrate. The reducing material contacts the switching fluid during switch state changes and reduces oxides on the switching fluid. The first substrate and a second substrate are then mated together, the substrates defining between them a cavity holding the switching fluid and one or more additional cavities, connected to the switching fluid cavity, that hold the actuating fluid mixed with the reducing material.